{
  "schemaVersion": "1.0.0",
  "systemVersion": "1.5.0",
  "kind": "field-and-contour",
  "scope": "two continuous fields; existing field plus point/line Crosspoints remain valid",
  "subject": "SMOKE",
  "layers": [
    {
      "subject": "SMOKE",
      "geometry": "field",
      "label": "煙",
      "unit": "AOD",
      "period": {
        "start": "2026-09-20T12:00:00Z",
        "end": "2026-09-20T12:00:00Z",
        "statistic": "instantaneous"
      }
    },
    {
      "subject": "AIR",
      "geometry": "contour",
      "quantityKind": "continuous",
      "colourEncoding": "single",
      "label": "PM2.5",
      "unit": "µg/m³",
      "levels": [
        10,
        25,
        40
      ],
      "levelLabels": true,
      "period": {
        "start": "2026-09-20T12:00:00Z",
        "end": "2026-09-20T12:00:00Z",
        "statistic": "instantaneous"
      }
    }
  ],
  "comparison": {
    "timeRelation": "aligned",
    "periodsVisible": true
  },
  "exampleOnly": true,
  "note": "Synthetic demonstration. Select thresholds from the actual quantity and dataset; do not treat these PM2.5 levels as health categories."
}